I have a 67 Dart with a 340. I have put in a new radiator ( 70-72 dart style ), the matching shroud, factory 18" 7 blade clutch fan with the short jaguar clutch. THat gave me 1 1/8" clearance between radiator and fan clutch. All of this has helped cool the engine some, but not enough because summer is not even here yet. Went for a short ride last night ( 55* ) and car ran at 185*. got home and let it idle about 15 minutes and it stayed about 195*. Before the clutch fan it would get over 200 idling. It has an 8 blade pump and 180* thermostat. Could the water be moving too fast too cool at idle? If it takes buying an aluminum radiator I will, but I would really like to make the stock cooling system work if possible. Any ideas?
engine still not cool enough
- Thread starter duster360
- Start date
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Mopar73340
Well-Known Member
Is the Jaguar clutch you installed a HD unit or a standard unit. As I said in another post on here, my experience with the heavier 7 blade fans is that the std duty clutches will not spin the fan fast enough at idle (to much slipage) and it tends to cause the engine to warm up at low speed/idle. I had the same issue. Now I run the same fan (7 Blade fan) and HD clutch and even on 90* days with the A/C on my cars sit right at the thermostat opening temp while at idle. The clutch is the only change I made and it corrected the issue I had that was exactly like you describe. This is using the assumption that the rest of your cooling system is in good cond.
THe one I got was the 7" thermal heavy duty. It's the only one they had listed. Got it at advance auto parts. It doesn't have the extra fins in the center like some of the other heavy duty ones I have seen.
Wheel Chock
Well-Known Member
What temperature are you trying to achieve? An engine that runs 5* above the rated opening point of the thermostat is not running hot. It's entirely possible that a thermostat rated at 180* might not actually open fully until 185*. Having the engine temp rise 10* after 15 minutes of idling is also not unusual. The only way to have it idle any cooler is to increase the air flow through the radiator by using an electric fan. I'd bet that if you put a large household electric fan running at high speed in front of the car at idle, the temperature would drop. Point an I/R temp gun at different areas of the engine such as the inlet and outlets for the radiator and you'll probably find the your current radiator is doing a pretty good job. The temp climbing at idle is an air flow not a coolant flow issue.
1968FormulaS340
Well-Known Member
I don't see an issue with your temps (at this point).
Some things you can check if you like……
How far is the fan into the shroud?
Do you have the rubber strip on the under front edge of your hood (seals against the core support).
Toss in some Water Wetter (any auto parts store).
Timing and air/fuel ratio correct?
Some things you can check if you like……
How far is the fan into the shroud?
Do you have the rubber strip on the under front edge of your hood (seals against the core support).
Toss in some Water Wetter (any auto parts store).
Timing and air/fuel ratio correct?
Snake
Mopar Nut
There is nothing wrong with those temps,heat is horse power.Hell I had a 66 Beaumont with a 396 BB that ran 205 and in stop and go 225 never boiled over.
67Dart273
Well-Known Member
I don't either
demon seed
The Original Demon Seed
Did you install a "high volume thermostat" when you installed the high volume pump (which an 8 blader is). Your temps are good now but could heat up in the summer.
I will look into a high volume thermostat and some water wetter. Scratch that, I will have both in the next couple days. I do have the rubber strip on the hood. Timing is close but carb could use a little more tuning. Fan is about right.
I used to have this engine in a truck with a 3 row radiator and it was very wide, with 6 blade flex fan. It would run 180* all day long, no matter the temp outside. I guess I was so used to that I guess I have made myself paranoid about the temps it runs in this car. I can for a fact say that the factory 7 blade clutch fan did help though.
Snake
Mopar Nut
Also that truck has a huge grill.
Josecuda
Well-Known Member
Why is this seal important for engine cooling ?
Because it forces more air through the grill and radiator rather than over the radiator through the gap that it fills.
Paladin06
Well-Known Member
Also there is a seal for the rear of the hood as well.
1968FormulaS340
Well-Known Member
Exactly . If you look at a modern car you will see that all holes and gaps in the core support are filled with something (foam tape, rubber, plastic plugs). This makes it so all the air is forced through the radiator (one of the reasons many cars can get away with those thin, cheese radiators).
Sometimes you will see people that have added an aftermarket radiator to their a-body (or any car for that matter) and suddenly their cooling goes in the toilet One reason I have seen is improper fit, Im talking that 1" gap all the way around the radiator that allows air to go around and not through (especially bad if you ditch your shroud at the same time).
Fill those gaps, plug those holes and your cooling efficiency will go up.
Snake
Mopar Nut
Also is it true if an engine temp is too low will it make less power and the spark plugs will suffer from not getting hot enough,anyone care to shed some light on that as well.I always thought if temps are to low the plugs will run rich?
It will run rich in that condition, because the plugs are not reaching operating condition and won't burn off the fuel completely.
Snake
Mopar Nut
You should wright a book StrokerScamp very very knowledgeable.No punt intended
Ha! Opinions vary. Lots more here smarter than I.
Not knockin your idea there...if it works, great. But that's not really addressin the problem......whatever it might be. That's just a mask.
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